Keith Clark

Timeline

1. 1964–1975

   Lecturer at Queen Mary College

   Born in 1943, he earns a first-class mathematics degree at Durham University's Hatfield College in 1964 and a second degree, in philosophy, at Cambridge in 1966. After a year teaching in Sierra Leone with Voluntary Service Overseas, he lectures in computer science in the mathematics department of Queen Mary College from 1969 to 1975. There he helps develop an automata theory course whose notes become a book in 1975.

2. 1975

   Logic programming group at Imperial

   A keen convert to logic programming, he guides Robert Kowalski through a formal languages and automata theory course at Imperial College London in 1975. He then moves to Imperial as a senior lecturer and joins Kowalski in setting up the logic programming group, which becomes the Logic and AI section of the Department of Computing.

3. 1976–1980

   Negation as failure

   He presents work on negation as failure at a 1976 logic programming workshop at Imperial and publishes the paper "Negation as Failure" in 1978. The paper describes a Horn clause theorem prover with a rule that infers not-P when every possible proof of P fails. In 1980, he earns a PhD from the University of London, with Kowalski as advisor, for the thesis Predicate Logic as a Computational Formalism.

4. 1980–1986

   Micro-PROLOG and Parlog

   In 1980, he and Frank McCabe found Logic Programming Associates, an Imperial College spin-off that develops and markets micro-PROLOG for microcomputers. Also in 1980, he and his student Steve Gregory bring committed-choice nondeterminism and stream-communicating and-parallelism into logic programming, a paradigm Japan's Fifth Generation project later adopts. The two design Parlog, a logic programming language for parallel computer architectures, and describe it in a 1986 paper in ACM Transactions on Programming Languages and Systems.

5. 1985–1987

   First president of the ALP

   Around 1985, Alvey Programme grants and his help let Imperial's logic programming group grow to about 50 people. In 1986, he becomes the first president of the newly founded Association for Logic Programming, and Imperial appoints him Professor of Computational Logic in 1987.

6. 1997

   Named a founder of logic programming

   In 1997, the Association for Logic Programming names him one of 15 Founders of Logic Programming, a group that also includes Alain Colmerauer, Robert Kowalski and J. Alan Robinson.

7. 1990–2015

   Go!, QuLog and TeleoR

   After 1990, he concentrates on rule-based languages for multi-agent and cognitive robotic applications, including Go!, a multi-threaded agent language he publishes with McCabe in 2004. With Peter Robinson of the University of Queensland, he builds QuLog, a typed logic, function and action rule language, and TeleoR, an extension of Nilsson's teleo-reactive procedures for robotic agents. A June 2015 talk at the University of British Columbia presents their multi-tasking TeleoR agent architecture.

8. As of October 2026

   Emeritus professor at Imperial

   He is an Emeritus Professor and Distinguished Research Fellow in the Department of Computing at Imperial College London. His research interests include multi-agent systems, cognitive robotics, multi-threaded symbolic programming languages and teleo-reactive procedures and plans.